1. Field of Invention
This invention relates to piperazineethylidenebenzocycloalkanes, pharmaceutical compositions containing them, and methods of using them to treat hypertension.
2. Prior Art
U.S. Pat. No. 4,130,646 issued to Vogt et al. on Dec. 19, 1978 discloses amongst others (1)-phenyl-(4)-substituted piperazines of the formula: ##STR2## where R.sub.1 is hydrogen, halogen, hydroxy, alkanoyloxy, alkoxy, alkylthio, alkyl, CF.sub.3 or --OCH.sub.2 O--; R.sub.2 is hydrogen, halogen, alkyl, alkoxy, alkylthio or CF.sub.3 ; m is 1, 2; and n is an integer of 0-2. The compounds are stated to be sedatives, muscle relaxants and neuroleptics.
Belgian Pat. No. 820,485 discloses dibenzo(a,e)cyclopropa(c)cycloheptene derivatives, useful as antidepressants and diuretics, of the formula: ##STR3## where Alk represents ethylene or propylene; NRR.sub.1 can be amonst others 4-methylpiperazino, 4-(2-hydroxyethyl)piperazine; and n is an integer of 1 or 2 depending on whether the dotted line is a single or double bond.
U.S. Pat. No. 4,199,582 issued to Oka et al on Apr. 22, 1980 discloses dihydronaphthalene compounds, useful as antihypertensives, for management of impaired cerebral circulation and as peripheral vasodilators. These compounds have the formula: ##STR4## where A is di(C.sub.1-4 alkyl)amino, or a 5-7 membered cyclic amino group, which may contain one oxygen; and n is an integer of 2 or 3.
A number of other references disclose piperazine derivatives which possess antihypertensive activity. One such reference is European Pat. No. 395 which discloses 2-(1-piperazinyl)tetralin compounds of the formula: ##STR5## where R.sub.1 can be hydroxy, C.sub.1-4 alkoxy, C.sub.1-20 alkanoyloxy, R.sub.2 and R.sub.3 are each hydrogen or as R.sub.1, or R.sub.1 and R.sub.2 on adjacent carbon atoms can be --OCH.sub.2 O--, and A is naphthyl.
U.S. Pat. No. 4,148,897 issued to Oka et al. discloses 1,2-dihydronaphthalenes, effective as cerebral and peripheral vasodilators, of the formula: ##STR6## where R.sup.3 is piperazinyl or morpholino which amonst others can both optionally be substituted with aralkyl.
Numerous antihypertensive agents of other chemical structures are known in the art. There is nevertheless a continuing need for additional antihypertensive agents because of the various side effects which can occur with existing agents.